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A. OHATWIN.

Sor ew Cutting Die Holder.

No. 239,445 Patented March 29,1881.

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mm Wily/ I fittest NITED STATES PATENT OFFICE.

AMBROSE OHATWIN, OF BROOKLYN, NEW YORK, ASSIGNOR TO ROBERT MITCHELL, OF MONTREAL, CANADA.

SCREW-CUTTl'NG-DIE HOLDE R.

SPECIFICATION forming part of Letters Patent No. 239,445, dated March 29,

Application filed September 28, 1880. (No model.)

To all whom it may concern:

Be it known that I, AMBROSE OHATWIN, of th t'city of Brooklyn, in the State of New York, but at present residing temporarily in the city and district of Montreal, in the Province of Quebec and Dominion of Canada, have invented anew and useful I mprovementin Screw- Outting-Die Holders, of which the following is a specification. V

The improvement is fully set forth in the fol-, lowing specification and claim.

In the accompanying drawings, Figure 1 is a perspective face or front view of my improved die-holderwith the jaws closed. Fig. 2 is a similar view with the jaws open preparatory to the insertion or removal of a tube.

Similarreference-lettersindicate corresponding parts in both figures.

A is the square base or foundation of the dieholder, adapted for insertion into the shiftin g head of the screwing-machine in the usual way.

B B are the separate halves or jaws of the die'holder, having their fulcrums or fixed centers of motion at a a, which a a are strong bolts fixed rigidly into the base-plate A, and having their outer ends connected, after passing through the jaws B B, by the link b, for the purpose of giving greater rigidity and strength. The opposite ends of the jaws are capable of lateral motion to an extent sufficient to allow the threaded end of the tube or bolt to pass freely out of the dies 0 0 when opened up, as shown in Fig. 2, and to come closely together, as in Fig. 1, when clamping the tube or bolt. They are thrown into and retained in their respective positions by the lever O, cam 01, and connecting-links g g, in conjunction with a throw-spring, j, pressing outwardly, and atQ tached at each end to the jaws B. This spring tends to force the jaws apart.

The lever O and cam d are preferably form ed in one piece, and have their common center of motion at e, which is a pin firmly attached to thebase-plate A. The cam 01 is formed so as to bear against the outer hollowed edge, f, of.

have this device operate smoothly, evenly, and 1 efficiently, the links 9 g must move together at all times, and to insure this a curve or saddle, l, is formed in the link 9, which enables it to straddle the center pin, 6.

Having thus described myinvention, Idesire to claim The herein-described die-holder, consisting of the face-plate A, jaws B, pivoted at the lower end, a, a, and having the curved springj reaching from one to the other, and tending to force the jaws open, the pin k, having a broad flat head, lever O, cam d, and links 9 g, all con structed and arranged to operate as herein set forth.

AMBROSE OHATWIN.

Witnesses:

R. HENNEssY, W. A. PHILLIPS. 

